What is the primary microorganism responsible for lactic acid fermentation in lambics?

The primary microorganism responsible for lactic acid fermentation in lambics is Lactobacillus. This type of bacteria is integral to the production of sourness in lambics, which are traditionally brewed in Belgium. Lactobacillus ferments sugar into lactic acid, contributing to the beer's tart flavor profile.

In the context of lambic fermentation, Lactobacillus often works alongside other microorganisms, such as Brettanomyces, which is responsible for many of the complex flavors in the beer but does not contribute significantly to lactic acid production. Pediococcus can also play a role in lactic acid production; however, it is generally considered a secondary lactic acid bacteria in the fermentation process of lambics. Saccharomyces, while essential for alcohol fermentation, does not participate in lactic acid fermentation. This multi-microbial approach to fermentation is what gives lambics their unique complexity and sourness, with Lactobacillus being the primary driver of lactic acid production.